Chapter 11 in this book is dedicated to pitfalls - or issues that should be noticed when building event processing applications that are not fully resolved by current products.
The book is implementation neutral, thus, the model described in this book can be implemented either in one of the products on in "roll your own", some have already used the book for design their own implementation. As for languages that have implemented the book's example ---- we issued a call for the community, and in this stage we have six implementation downloadable -- four commercial products which have free development versions: Apama, Streambase, CCL (Coral8 now Sybase) and ruleCore, and two open sources - Esper and Etalis. We expect to have more implementations -- don't have Drools.